US1968441A - Process of preparing lacquers, varnishes, or the like - Google Patents

Description

Patented July 31, 1934 PRooEss F PREPARING LAoQUERs, VARNISHES, on THE LIKE Ernst Elbel and Fritz Seebach, Erkner, near Berlin, Germany, .assignors to Bakelite Gesellschaft mit beschrankter Haftung, Berlin, Ger- ,many

No Drawing. Application January 22, 1930, Serial No. 422,683. In Germany January 29, 1929 lolaims. (oi. 134-26) I v According to our prior'U, S. application Ser..No. the finished lacquer andconverted into .a resitole, 295,344 filed July 25, 1928, lacquers or varnishes and any water remaining as a result of the convencan be prepared from resit'oles, that is, synthetic sion that has not been eliminated during the resinous products of a hardenable'nature which course of heating the resole solution can .be re-.

are in an intermediate or E state wherein they are moved by distillation under normal pressure or a {if} not fusible or soluble but swell in the usual sol partial vacuum. The elimination'oi the waterof vents. Acc'ordingto that disclosure lacquers or reaction is very. important for otherwise the varnishes are obtained by dissolving resitoles in varnishes are likely to exhibit cloudiness and suitable solvents, either alone'or with the additroublesome pr p It 13.84180 possible 30' tion of other resins, under normal atmospheric, proceedas, for instance, by interrupting the heat& 65

reduced or increased pressure and at ordinary or me, o t a p only of the resole is n te elevated temperatures. It has now been found 11 3 ait upon further investigation that lacquers and var- It is n t es ntial t be in wi h re l nishes consisting of resitole solutions are obtained Ri sito Solutions c be Obtained from Home 15 more readily and more advantageously in comhardenable condensat o reaction Products, 70. parison with the process disclosed in thefaforethe so-called novolaks, by dissolving t said prior application, according to whichthe s' her wi h hardeni agents, such as aldehydes' resitolesare first prepared and then brought into or their polymer hy ib Substances solution, by causing the formation of the resitoles as hexamethylenetetmmine, baSicailly acting in the presence of a greater or less amountof substances as oxides or hydroxides, or other suit- 75 substances that are suitable as solvents. While able metal compounds inappropriate solvents the solvents mentionedin the prior application' and th n beginning t are remarkably good solvents for resitoles,'their Resole solutions can be heated in the usual solution therein, however, requires'care in avoids ma ne u der ed increased- DYBSSUTE 2s ing overheating the solutions to thereby' causea oth tu lv r synthetic, hardenable or on-- so partialconversion of: the resitoles into resiteshardenable resins can be added to a solution bethat is, the final infusible and practically infore, dur after t healing p AS soluble or C products-and consequent precipi- V nts there can, for example, be used hydrogentation of the resins. According to the process of ated phenols, cyclic ketones or the homologs of the present invention not only are the lacquers these bodies, besides iuriural. Organic liquids 5.. and varnishes prepared from resoles or harden- Which have no solvent power as tetralin or homoable synthetic resins in an initial fusible and benZol can be employed in admixture with these soluble or A condition in one operation but the solvents. Furthermore one can proceed by adddanger of precipitation through overheating is ing to the solution catalyzers, as nitrophenols,

- 0vercome. which accelerate the hardening of the lacquer 90 In accordance with this invention resoles are film- Finally plasticizers and fireproofing comdissolved in suitable amounts of a solvent or solpounds can be included. Suitable plasticizers, vents and converted to the resitole form by heatbesides the triamylphosphates mentioned in the ing the solution. The greater the amount of solprior application, are oils, chlorinated or hy- 40 vent used the less is the danger of overheating the drogenated naphthalenes, etc. 95

' 'resitoles through contact with parts of the appa- One can for example proceed as follows:

ratus that are overheated to cause formation of 1. 50 kilos resole are dissolved in 25 kilos cycloinsoluble products. For example, the entire hexanol and heated until the at first thinly liquid amount of solvent to be used can be added to a substance starts to solidify; then 59 kilos cyclo- -1'esole, as described in the prior application in hexanol are added and heated until solution is 100 i connection with resitoles, to yield directly resitole completed. The solution is then poured into wood lacquers upon sufiicient heating. The technical alcohol to obtain a thin lacquer.

procedure however is subject to wide variation; 2. 30 parts by weight of resole are dissolved in the various methods described in the prior appli- 20 parts by weight of cyclohexanol and are heated --cation are adaptable to the present case. Thus at about 110 C. until the resole in the solution 105 a resole can be dissolved in a greater amount of is completely converted into resitole. This is solvent than that required for a varnish and the recognized by the fact that, after approximately excess solvent can be removed from the final to 1 hours heating a lively gas formation sets resitole solution by distillation. Or a resole can in accompanied by more or less violent foaming.

be dissolved in an amount of solvent desired in The gases and foaming are caused by the water 11:

forming during the conversion or the resoles into resitoles, which does not mix with cyclohexanol. The removal of the water may be completed by heating under a partial vacuum or with substances acting as dehydrating agents, such as calcium chloride.

3. 27 parts by weight of novolak and 2.7 parts by weight of hexamethylenetetramine are dissolved in 20 parts by weight of cyclohexanol, and the procedure is followed as in Example 2.

The resitole solutions obtained according to Examples 2 and 3 may likewise be mixed with wood alcohol or other varnish solvents.

The following definitions are intended for the terms resole, resitole, resite and novolak. A resole is a resin of the type hardenable by heat to a final infusible insoluble condition but reacted only to the stage where it still melts when heated and is soluble in acetone; this is also known as the A-stage or A condition and the resin at this stage is known as an A-type resin. A resitole is a resin of the same type as a resole but further reacted to a B state or B type where it has become infusible, i. e., it does not melt although it softens somewhat upon heating and it is insoluble but swells in acetone. A resite is the same heat-hardenable resin but reacted to the final or C stage or C product, characterized by complete insolubility in acetone and infusible without any material softening upon heating. A novolak is a distinctly different type of resinous reaction product in that practically speaking it does not harden upon heating to an insoluble infusi'ble condition but remains soluble and fusible. The resins here defined are those made from the phenols or their derivatives with a methylene or aldehyde agent as is well understood by those skilled in the art.

We claim:

1. A process of making lacquers and varnishes containing hardenable phenol-formaldehyde resins which comprises dissolving a phenol-formaldehyde resin in the resole stage at which it still melts when heated and is soluble in alcohol in a solvent of the group consisting of hydrogenated aromatic hydrocarbons, hexahydrogenated phenols and their esters and hydroaromatic cyclic ketones, heating the solution at converting temperature until a conversion of phenol-formaldehyde resin of the resole stage into a phenol-formaldehyde resin of the resitole stage takes place, which resitole is thermoplastic but infusible and is insoluble in alcohol but swells therein, and adding liquids if necessary to maintain the product fluid.

2. Process of making lacquers and varnishes containing hardenable phenol-formaldehyde resins which comprises dissolving a permanently soluble and fusible phenol-formaldehyde resin together with a hardening agent in a solvent of the group consisting of hydrogenated aromatic hydrocarbons, hexahydrogenated phenols and their esters and hydroaromatic cyclic ketones, heating the solution at converting temperature until a conversion of fusible resin into a phenolformaldehyde resin which is thermoplastic but infusible and which is insoluble in alcohol but swells therein takes place, and adding liquids if necessary to maintain the product fluid.

3. A process according to claim 1, characterized therein that organic liquids which do not dissolve phenol-formaldehyde resin of the said resitole stage are used in conjunction with said solvent.

4. As a, composition of matter a solution of a phenol-formaldehyde resin in an organic solvent of the group consisting of hydrogenated aromatic hydrocarbons, hexahydrogenated phenols. and their esters and hydro-aromatic cyclic ketones, which composition is prepared by dissolving in said organic solvent a preformed phenol-formaldehyde resin which has been reacted to a stage at which it is thermoplastic and fusible and at which it is soluble in alcohol, and converting said resin to a stage of resinification at which it is thermoplastic but infusible and at which it is insoluble in alcohol but swells therein by heating the so-prepared solution at converting temperature until said conversion has been effected.

ERNST ELBEL.

FRITZ SEEBACH.